What the black box will tell of AirAsia crash

With the discovery of the wreckage of AirAsia Flight 8501, investigators are one step closer to determining the cause of the accident. There was bad weather in the area around the time of the crash.

They will also try to determine the plane's airspeed, whether mechanical systems failed and how the pilots responded before the plane went down.

The answers may come from the plane's black boxes, presumably still underwater. U.S. Navy ships sent to help the recovery have sonar equipment which can detect the underwater locator beacon. The device's sound, a high-pitched chirp is what they'll be looking for.

The so-called black box is actually orange and is located in the tail section of an Airbus A-320. It contains the flight data recorder, with the last 25 hours of information about the plane's altitude, air speed and engine performance. There's also the cockpit voice recorder, with the final two hours of pilot conversations and interaction with air traffic control.

Earlier this year we were given an unprecedented look at how National Transportation Safety Board engineers open the shell to extract the memory board of the recorders. It's just about the size of your cellphone and within the box, it's almost indestructible.

"They have to survive salt water immersion and immersion up to 20,000 feet," said Dr. Joe Kolly, the NTSB's director of research and engineering. "We've been successful in recovering data from submerged aircraft."

The NTSB has been monitoring the situation, but so far has not been asked to participate. Because Airbus is a French company, that country's equivalent of the NTSB has already sent a team of investigators to the area.

Investigators can tell an awful lot about what happened from the debris field. A widely scattered debris field suggests in-flight breakup. But a more focused debris field may suggest that the plane hit the water relatively intact -- similar to what happened to Air France Flight 447 in 2009 in the Atlantic. Air speed indicators were lost in that case. But it's really too early to tell and that's why the black boxes are so important.